Recently launched in Europe, Selincro is a potentially important new product for Lundbeck, which needs new drugs to replace revenue from those going off patent. However, its unusual market niche means sales prospects are uncertain.

The National Institute for Health and Care Excellence (NICE) said in draft guidance on Thursday that some 600,000 people dependent on alcohol should have access to the once-daily drug, also known as nalmefene, to help them fight addiction.

NICE added it expected to publish final guidance in November 2014 on the use of Selincro, which costs 42.42 pounds for a pack of 14 tablets.

Lundbeck believes Selincro has the potential to generate annual sales of 2.0-2.5 billion Danish crowns (£213-266 million) in all markets, although Chief Executive Ulf Wiinberg told Reuters in March that getting there could be a long haul.

Selincro works by blocking the action of opioid receptors in the brain and it is approved for the reduction of alcohol consumption in people dependent on drink, alongside counselling.

(Reporting by Ben Hirschler, editing by David Evans)